I'm on holiday in the south of Spain and I was sat on the terrace on Friday morning on the 27th May at 10:06 am just chatting with the wife and watching the world go by as you do.
It wasn't until I looked out towards the sky I noticed a weird vapour trial. So I grabbed my phone and took a video. Well you could say it's a plane? You could, but the problem is it's a NO FLY ZONE! So anyway, I went in side and came back out at 10:22 and saw that there was additional trials now! I was like WTF?! So I took another video and put them both together. You can see the difference 12 minutes has made! Check out the videos.
Not sure what it could have been but what I can tell you is i didn't hear or see anything!